Safety and Immunogenicity of Locally Manufactured New (HL-OCV) Oral Cholera Vaccine

Background : Cholera continues to be a major cause of morbidity and mortality in low income countries including Bangladesh. It is estimated that there are at least 300,000 severe cases and over 4,500 deaths in Bangladesh each year1. The overall morbidity for cholera remains high. A global stockpile of OCV has been created by WHO in 2013 for epidemic and outbreak settings30. However, the global demand for the vaccine far exceeds the present supply for both epidemic and also endemic settings3. It can be envisioned that local production of an affordable OCV for high risk population in endemic settings will improve the present scenario in Bangladesh and other countries.

Knowledge gap: The WHO recommends OCV for use in both endemic and epidemic cholera settings4. At present there are two vaccines that are WHO prequalified. These include Dukoral which is registered in Bangladesh and in over 50 countries. However, the disadvantage of use of Dukoral is that its current price is expensive for Bangladesh and other developing countries. In addition, the need for buffer to formulate the vaccine makes it less fieldable for mass vaccination programs.Another whole killed OCV, ShancholTM, which is WHO prequalified, is based on similar bacterial components as Dukoral and licensed in India but not in Bangladesh. Although this vaccine is relatively affordable it may not be sufficiently cost effective for the Government of Bangladesh to implement it in our poor endemic settings. At present, the vaccine is in short supply and will not be able to meet the global demands. In order to increase supply of OCV and make the vaccine more affordable, MSD Wellcome Trust Hilleman Labs. Pvt. Ltd in collaboration with Goteberg University, Sweden has engineered new oral cholera vaccine HL-OCV,consisting of formaldehyde-inactivated recombinant V.cholerae strain ,MS 1568 expressing both Ogawa and Inaba antigens. The vaccine formulation is quantified on total O1 lipopolysaccharide ,LPS content which is matched to that of ShancholTM ,not less than 600 mcg/ml LPS for O1; Formulation A and higher than Shanchol ,not less than 900 mcg/ml LPS for O1; Formulation B. The vaccine technology is transferred to local manufacturer ,INCEPTA in Bangladesh.

Relevance: The study of this locally manufactured new HL-OCV, among children and adults will be able to give us information regarding the safety and immunogenicity of two different formulations of vaccine, based on LPS content. The study will not only identify safe formulation among the two formulation A or B, but will also be able to show superiority of higher LPS formulation in most naive population in children who are 1-5 years of age. Results of the study will be able to identify and select most suitable formulation in Phase II study for licensure in Bangladesh. This study will further pave the way forward for field studies which could establish field efficacy of vaccine compared to existing vaccines in Bangladesh.

Hypothesis : Locally produced orally administered whole cell inactivated HL-OCV test formulations A and B are safe and immunogenic in adults and children in Bangladesh as compared to Shanchol TM.

Objectives: The objective of this study is to determine most safe and immunogenic formulation for new oral cholera vaccine HL-OCV, and comparing with licensed vaccine ShancholTM.

Inclusion criteria

• Age: 1years to less than 5 years for the younger children group; 5- less than18 years for older children and adolescent group and 18- 45 years (inclusive) for the adult group.
• Sex: Male, Female, Transgender.
• Consent: Informed consent from study participants and guardian in case of children along with assent in children 11-17 years (inclusive) of age.
• Apparently healthy.

Exclusion criteria

• Suffering from diarrhoea or abdominal pain or vomiting in the past 24 hours or diarrhoea lasting for more than 2 weeks in the past 6 months
• History of taking oral cholera vaccine.
• History of taking any other live or killed enteric vaccine in the last 8 weeks.
• History of anaphylaxis or serious vaccine reaction.
• Currently use of any immunosuppressive or immune-modifying drugs.
• Receipt of blood or blood products or parenteral immunoglobulin preparation in the past 3 months.
• Currently on antimicrobial therapy (taking antibiotics within 24 hours during screening and vaccination).
• Severe malnutrition defined as wt-for-ht z-score <-3.0 with or without oedema.
• For married females pregnancy or plans to become pregnant during the study period (as determined by verbal screening) will be excluded. In addition, pregnancy test will be done by pregnancy strip test before each day of vaccination (Day 0 and day 14) for married female.
• Culture positive V. cholerae, ETEC, Salmonella and Shigella in stool.